22737-96-8Relevant academic research and scientific papers
Z -isomerization of retinoids through combination of monochromatic photoisomerization and metal catalysis
Kahremany, Shirin,Sander, Christopher Lane,Tochtrop, Gregory P.,Kubas, Adam,Palczewski, Krzysztof
supporting information, p. 8125 - 8139 (2019/09/19)
Catalytic Z-isomerization of retinoids to their thermodynamically less stable Z-isomer remains a challenge. In this report, we present a photochemical approach for the catalytic Z-isomerization of retinoids using monochromatic wavelength UV irradiation treatment. We have developed a straightforward approach for the synthesis of Z-retinoids in high yield, overcoming common obstacles normally associated with their synthesis. Calculations based on density functional theory (DFT) have allowed us to correlate the experimentally observed Z-isomer distribution of retinoids with the energies of chemically important intermediates, which include ground- and excited-state potential energy surfaces. We also demonstrate the application of the current method by synthesizing gram-scale quantities of 9-cis-retinyl acetate 9Z-a. Operational simplicity and gram-scale ability make this chemistry a very practical solution to the problem of Z-isomer retinoid synthesis.
Catalytic synthesis of 9-cis-retinoids: Mechanistic insights
Kahremany, Shirin,Kubas, Adam,Tochtrop, Gregory P.,Palczewski, Krzysztof
supporting information, p. 10581 - 10595 (2019/07/22)
The regioselective Z-isomerization of thermodynamically stable all-trans retinoids remains challenging, and ultimately limits the availability of much needed therapeutics for the treatment of human diseases. We present here a novel, straightforward approach for the catalytic Z-isomerization of retinoids using conventional heat treatment or microwave irradiation. A screen of 20 transition metal-based catalysts identified an optimal approach for the regioselective production of Z-retinoids. The most effective catalytic system was comprised of a palladium complex with labile ligands. Several mechanistic studies, including isotopic H/D exchange and state-of-the-art quantum chemical calculations using coupled cluster methods indicate that the isomerization is initiated by catalyst dimerization followed by the formation of a cyclic, six-membered chloropalladate catalyst-substrate adduct, which eventually opens to produce the desired Z-isomer. The synthetic development described here, combined with thorough mechanistic analysis of the underlying chemistry, highlights the use of readily available transition metal-based catalysts in straightforward formats for gram-scale drug synthesis.
METHOD FOR SYNTHESIS OF 9-CIS-BETA-CAROTENE AND FORMULATIONS THEREOF
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, (2017/12/29)
The present invention relates to a method for total chemical synthesis of 9-cis-β-carotene (9CBC), and further provides stable formulations thereof.
Substrate specificity and subcellular localization of the aldehyde-Alcohol redox-Coupling reaction in carp cones
Sato, Shinya,Fukagawa, Takashi,Tachibanaki, Shuji,Yamano, Yumiko,Wada, Akimori,Kawamura, Satoru
, p. 36589 - 36597 (2014/01/17)
Our previous study suggested the presence of a novel conespecific redox reaction that generates 11-cis-retinal from 11-cisretinol in the carp retina. This reaction is unique in that 1) both 11-cis-retinol and all-trans-retinal were required to produce 11-cis-retinal; 2) together with 11-cis-retinal, all-trans-retinol was produced at a 1:1 ratio; and 3) the addition of enzyme cofactors such as NADP(H) was not necessary. This reaction is probably part of the reactions in a cone-specific retinoid cycle required for cone visual pigment regeneration with the use of 11-cis-retinol supplied from Mueller cells. In this study, using purified carp cone membrane preparations, we first confirmed that the reaction is a redox-coupling reaction between retinals and retinols. We further examined the substrate specificity, reaction mechanism, and subcellular localization of this reaction. Oxidation was specific for 11-cis-retinol and 9-cis-retinol. In contrast, reduction showed low specificity: many aldehydes, including all-trans-, 9-cis-, 11-cis-, and 13-cis-retinals and even benzaldehyde, supported the reaction. On the basis of kinetic studies of this reaction (aldehyde-alcohol redox-coupling reaction), we found that formation of a ternary complex of a retinol, an aldehyde, and a postulated enzyme seemed to be necessary, which suggested the presence of both the retinol- and aldehydebinding sites in this enzyme. A subcellular fractionation study showed that the activity is present almost exclusively in the cone inner segment. These results suggest the presence of an effective production mechanism of 11-cis-retinal in the cone inner segment to regenerate visual pigment.
Synthesis of 11-cis-retinoids by hydrosilylation-protodesilylation of an 11,12-didehydro precursor: Easy access to 11- and 12-mono- and 11,12-dideuteroretinoids
Bergueiro, Julián,Montenegro, Javier,Saá, Carlos,López, Susana
supporting information, p. 14100 - 14107 (2013/01/15)
An expeditious, highly efficient approach to 11-cis-retinoids was achieved by semihydrogenation of a readily available 11-yne precursor through a hydrosilylation-protodesilylation protocol. The complete chemo-, regio-, and syn-stereoselectivity of the method also allowed direct access to 11- and 12-monodeutero-, and 11,12-dideutero-11-cis-retinoids. The analogous trans series was not accessible by this route, and was synthesized by means of Hiyama coupling. Copyright
Cross-coupling reactions of organosilicon compounds in the stereocontrolled synthesis of retinoids
Bergueiro, Julian,Montenegro, Javier,Cambeiro, Fermin,Saa, Carlos,Lopez, Susana
, p. 4401 - 4410 (2012/06/01)
This paper presents a full account of the use of Hiyama cross-coupling reactions in a highly convergent approach to retinoids in which the key step is construction of the central C10-C11 bond. Representatives of two families of oxygen-activated dienyl silanes (ethoxysilanes and silanols) and of all reported families of "safety-catch" silanols (siletanes, silyl hydrides, allyl-, benzyl-, aryl-, 2-pyridyl- and 2-thienylsilanes) were regio- and stereoselectively prepared and stereospecifically coupled to an appropriate electrophile by treatment with a palladium catalyst and a nucleophilic activator. Both all-trans and 11-cis-retinoids, and their chain-demethylated analogues, were obtained in good yields regardless of the geometry (E/Z) and of the steric congestion in each fragment. This comprehensive study conclusively establishes the Hiyama cross-coupling reaction, with its mild reaction conditions and stable, easily prepared, ecologically advantageous silicon-based coupling partners, as the most effective route to retinoids reported to date.
Laser flash photolysis study on the retinol radical cation in polar solvents
El-Agamey, Ali,Fukuzumi, Shunichi
scheme or table, p. 6437 - 6446 (2011/10/10)
Laser flash photolysis (LFP) of retinol in argon-saturated methanol gives rise to a transient at 580 nm (transient A). Formation of transient A is accompanied by a transient growth at 370 nm. The rate of this growth is retinol concentration-dependent. The transient growth at 370 nm was removed in the presence of N2O, which is known to scavenge solvated electrons. These results can be interpreted by formation of retinol+ (λmax = 580 nm) and solvated electrons following LFP of retinol. Subsequently, the solvated electrons are rapidly scavenged by retinol to form retinol- (λmax = 370 nm in methanol). On the other hand, transient A is not ascribed to the retinyl cation, as was previously proposed, because the retinyl cation, generated from LFP of retinyl acetate, and transient A show different reactivities towards halide ions (e.g. kBr = 1.7 × 109 and 1.51 × 1010 M-1 s-1 respectively, in acetonitrile). After demonstrating the identity of transient A as retinol+, its reactions with carotenoids were examined in air-saturated polar solvents. In the presence of carotenoids, an enhancement in the decay of retinol+ was observed and was accompanied by formation of the corresponding carotenoid radical cations via electron transfer from carotenoids to retinol+. Furthermore, the reactivity of retinol+ towards pyridine derivatives was investigated in air-saturated polar solvents. It was found that the decay of retinol + was accelerated with concomitant formation, with the same rate, of a transient at 370 nm. Similar observations were obtained with increasing pH of air-saturated aqueous 2% Triton X-100 of retinol+. The 370 nm (or 380 nm in the case of Triton X-100) transient is attributed to the base adducts or deprotonated neutral radicals. On the basis of these results, the reactivities of the retinyl cation and retinol+ are compared and the consequences of retinol+ formation within biological environments are discussed.
Syntheses of 13C2-labelled 11Z-retinals
McLean, Neville J.,Gansmuller, Axel,Concistre, Maria,Brown, Lynda J.,Levitt, Malcom H.,Brown, Richard C.D.
supporting information; experimental part, p. 8404 - 8410 (2011/11/12)
To enable solid-state NMR investigations of the rhodopsin chromophore and its photointermediates, a series of 11Z-retinal isotopomers have been synthesised containing pairs of adjacent 13C labels at C9/C10, C10/C11 or C11/C12, respectively. The C9 labelled carbon atom was introduced through the Heck reaction of a 13C-labelled Weinreb acrylamide derivative, and the label at the C12 position derived from a 13C-containing ethoxy Bestmann-Ohira reagent. The 13C labels at C10 and C11 were introduced through the reaction of β-ionone with labelled triethyl phosphonoacetate.
Hiyama cross-coupling reaction in the stereospecific synthesis of retinoids
Montenegro, Javier,Bergueiro, Julian,Saa, Carlos,Lopez, Susana
body text, p. 141 - 144 (2009/07/04)
The first application of the Hiyama reaction to the synthesis of retinoids is reported. A range of organosilicon moieties (siloxanes, silanols and three kinds of "safety-catch" silanols) were successfully coupled, under activation, to obtain trans-retinol or 11-cis-retinol with high yield and stereoselectivity. The advantageous properties of the silicon-based coupling partners and the mild reaction conditions firmly establish the Hiyama reaction as a viable (even superior) alternative to the traditional Suzuki and Stille couplings in the retinoid field.
